Nichrome and tantalum nitride resistor films are well characterized and their limitations are well understood. Nichrome thin film precision resistors have been the material of choice for many years for use in hybrid microcircuits and resistor networks. Likewise, the deposition processes used to create these films have been described. In general, deposited films in excess of a few hundred angstroms can produce sheet resistivities of 50 to 350 ohms/square for nichrome and 50 to 150 ohms/square for tantalum nitride. Long term stability of properly stabilized and trimmed nichrome resistors results in significantly less than a 0.5% change in value over 1000 hours at 125° C. when in air. Nichrome resistors are sensitive to moisture under typical bias loads in circuit applications. This requires the resistors to be coated with a moisture resistant conformal coating. The mitigation for moisture susceptibility of coating the resistors adds expense and additional testing requirements during fabrication. Such coatings are problematic and have led to yield loss, extensive rework procedures, and system failures in critical subsystems. Many system manufacturers require the use of high precision and reliable thin film resistors, particularly for complicated designs. It would be useful to be able to provide a thin film resistor that offers chemical and thermal stability along with a temperature coefficient of electrical resistance similar to that of nichrome (i.e., low bulk resistivity).
Titanium Carbide (TiC) has a low bulk resistivity of 150 ohm/square, chemical inertness, mechanical strength, and a high melting point of about 3500° K. However, with respect to temperature sensitive semiconductor substrates, TiC films are difficult to deposit at room temperature using conventional vacuum deposition. It would be useful to be able to fabricate a thin film resistor on a temperature sensitive substrate without damaging the substrate such that the resulting thin film resistor has high chemical and mechanical stability while still providing sufficiently low bulk resistivity.